SuperBeam is a free app that offers easy and fast sharing files between Android 4.0+ devices using WiFi Direct. You pair devices using QR Code scanning (with the included scanner) or NFC if available (just like Samsung's proprietary S-Beam).

Checkout the video below to see it in action:

Features:

Share files between devices using NFC or QR code scanning.

Blazing fast transfer speeds using WiFi direct.

Switches to hotspot mode automatically for devices that doesn't support WiFi direct.

Can use existing WiFi network connection between devices.

Share single or multiple files of any type (photos, videos, zip files, APK's... You name it!)

A note about WiFi direct
SuperBeam creates an access point using Android's WiFi direct API's. This essentially works like hotspot mode in old devices, but it is guaranteed to work on newer devices like Nexus 7. Moreover, this mode allows older devices to connect and receive files without having to support WiFi direct's peer-to-peer connections and, more importantly, it gets rid of the annoying "accept connection" prompt.
Also, please note that this mode is currently supported by Android versions 4.1 and greater. On older versions, SuperBeam will fallback to the older hotspot mode.

Please try it and let me know what you think. If you have any issues or suggestions, please feel free to contact me via email or reply to this thread.